(a) Field
The invention relates to a liquid crystal display and a manufacturing method thereof.
(b) Description of the Related Art
A liquid crystal display (“LCD”) is one of the flat panel displays which have been most widely used. In the LCD, a voltage is applied to an electrode to rearrange liquid crystal molecules of a liquid crystal layer so as to control an amount of transmitted light.
The LCD may be made to be slimmer but has side visibility lower than front visibility. To overcome the above problem, various types of liquid crystal arrays and driving methods have been developed. As a method for implementing a wide viewing angle, an LCD in which a pixel electrode and a common electrode are disposed on a single substrate has drawn much attention.
In the LCD, an oxide thin film transistor (“TFT”) has been manufactured using a self-aligned bottom gate. The self-aligned bottom gate is as follows. First, a gate electrode is disposed on a glass substrate, a gate insulating layer including a silicon oxide layer (SiO2) is provided to cover the gate electrode, an oxide semiconductor is disposed on a gate insulating layer, and then an excimer laser, for example, an excimer laser using Xenon-chloride (Xecl) having a wavelength of about 308 nanometers (nm), and the like is irradiated from a bottom portion of the glass substrate. In this case, a laser beam is irradiated to the oxide semiconductor using the gate electrode as a light blocking mask, in which a region to which the laser beam is irradiated becomes a conductor.